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Inserted text in green WW HEADERS_END A happy number is one where the repeated process of squaring and adding the digits eventually gives an answer of 1. A Happy Number is one where the repeated process of squaring and adding the digits eventually gives an answer of 1. For example: 13 * EQN:13->1^{2}+3^{2}=1+9=10 * EQN:10->1^{2}+0^{2}=1 * EQN:1->1^2=1 ... and so on. If a sequence like this reaches 1 it will stay there. 13 is a Happy Number! However some numbers do not reach one. For example: 14 * EQN:14->1^{2}+4^{2}=1+16=17 * EQN:17->1^{2}+7^{2}=1+49=50 * EQN:50->5^{2}+0^{2}=25 * EQN:25->2^{2}+5^{2}=4+25=29 * EQN:29->2^{2}+9^{2}=4+81=85 * EQN:85->8^{2}+5^{2}=64+25=89 * EQN:89->8^{2}+9^{2}=64+81=145 * EQN:145->1^{2}+4^{2}+5^{2}=1+16+25=42 * EQN:42->4^{2}+2^{2}=16+4=20 * EQN:20->2^{2}+0^{2}=4 * EQN:4->4^{2}=16 * EQN:16->1^{2}+6^{2}=1+36=37 * EQN:37->3^{2}+7^{2}=9+49=58 * EQN:58->5^{2}+8^{2}=25+64=89 which we've seen before... 14 is an Unhappy Number. This procedure is an example of a Number Chain ---- * http://en.wikipedia.org/wiki/Happy_number * http://mathworld.wolfram.com/HappyNumber.html